Editing Marine mammal (section)

==Ecology==
===Dietary===
[[File:Killer Whale Tipe B.jpg|thumb|[[Killer whale]] hunting a [[Weddel seal]]|alt=A killer whale sticking the front end of its body out of the water onto a floating piece of sea-ice to grab a dark-brown seal with light-brown-spots]]

All cetaceans are [[carnivorous]] and [[predatory]]. Toothed whales mostly feed on fish and [[cephalopod]]s, followed by [[crustacean]]s and [[bivalve]]s. Some may forage with other kinds of animals, such as other species of whales or certain species of [[pinniped]]s.<ref name=thepinnipeds/>{{rp|169}}<ref>{{cite book |last1=Klinowska |first1=Margaret |last2=Cooke |first2=Justin |year=1991 |title=Dolphins, Porpoises, and Whales of the World: the IUCN Red Data Book |publisher=IUCN Publications |location=Columbia University Press, NY |url=https://portals.iucn.org/library/sites/library/files/documents/RD-1991-001.pdf|isbn=978-2-88032-936-5|oclc=24110680}}</ref> One common feeding method is herding, where a pod squeezes a school of fish into a small volume, known as a [[bait ball]]. Individual members then take turns plowing through the ball, feeding on the stunned fish.{{sfn|Perrin|2009|loc=pp. 570–572}} Coralling is a method where dolphins chase fish into shallow water to catch them more easily.{{sfn|Perrin|2009|loc=pp. 570–572}} [[Killer whale]]s and [[bottlenose dolphin]]s have also been known to drive their prey onto a beach to feed on it. Killer whales have been known to paralyze [[great white shark]]s and other sharks and rays by flipping them upside down.<ref>{{cite web |last=((U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service)) |title=Coastal Stock(s) of Atlantic Bottlenose Dolphin: Status Review and Management Proceedings and Recommendations from a Workshop held in Beaufort, North Carolina, 13 September 1993&nbsp;– 14 September 1993 |url=http://www.nmfs.noaa.gov/pr/pdfs/species/coastalbottlenosestock.pdf |url-status=dead |pages=56–57 |access-date=13 June 2016 |archive-date=7 October 2006 |archive-url=https://web.archive.org/web/20061007090154/http://www.nmfs.noaa.gov/pr/pdfs/species/coastalbottlenosestock.pdf }}</ref><ref>Gregory K. Silber, Dagmar Fertl (1995) – ''Intentional beaching by bottlenose dolphins (Tursiops truncatus) in the Colorado River Delta, Mexico.''</ref> Other whales with a blunt snout and reduced dentition rely on [[suction feeding]].<ref>{{cite book|last=Berta, A.|author2=Sumich, J. L.|author3=Kovacs, K. M.|year=2015|title=Marine Mammals: Evolutionary Biology|publisher=Academic Press|page=430|isbn=978-0-12-397002-2|oclc=905649783|location=London}}</ref> Though carnivorous, they house [[gut flora]] similar to that of terrestrial herbivores, probably a [[Vestigiality|remnant]] of their herbivorous ancestry.<ref>{{cite journal|first1=Jon G.|last1=Sanders|first2=Annabel C.|last2= Beichman|first3=Joe|last3=Roman|first4=Jarrod J.|last4=Scott|first5=David|last5=Emerson |first6=James J. |last6=McCarthy|author7-link=Peter Girguis|first7=Peter R.|last7=Girguis|year=2015|title=Baleen whales host a unique gut microbiome with similarities to both carnivores and herbivores|journal=Nature Communications|volume=6|pages=8285| doi=10.1038/ncomms9285|pmid=26393325|pmc=4595633|bibcode=2015NatCo...6.8285S}}{{open access}}</ref>

Baleen whales use their baleen plates to sieve plankton, among others, out of the water; there are two types of methods: lunge-feeding and gulp-feeding. Lunge-feeders expand the volume of their jaw to a volume bigger than the original volume of the whale itself by inflating their mouth. This causes grooves on their throat to expand, increasing the amount of water the mouth can store.<ref>{{cite journal|first1=A. W.|last1=Vogle|first2=Margo A.|last2=Lillie|first3=Marina A.|last3=Piscitelli|first4=Jeremy A.|last4=Goldbogen|first5=Nicholas D.|last5=Pyenson|author5-link=Nicholas Pyenson|first6=Robert E.|last6= Shadwick|year=2015|title=Stretchy nerves are an essential component of the extreme feeding mechanism of rorqual whales|journal=Current Biology|volume=25|issue=9|pages=360–361|doi=10.1016/j.cub.2015.03.007|pmid=25942546|doi-access=free|bibcode=2015CBio...25.R360V }}</ref><ref>{{cite journal|url=https://www.americanscientist.org/issues/pub/the-ultimate-mouthful-lunge-feeding-in-rorqual-whales/|first=Jeremy A.|last=Goldbogen|year=2010|title=The Ultimate Mouthful: Lunge Feeding in Rorqual Whales|journal=American Scientist|volume=98|pages=124–131|number=2|doi=10.1511/2010.83.124 |jstor=27859477}}{{open access}}</ref> They ram a baitball at high speeds in order to feed, but this is only energy-effective when used against a large baitball.<ref>{{cite journal|title=Mechanics, hydrodynamics and energetics of blue whale lunge feeding: efficiency dependence on krill density|first1=J. A.|last1=Goldbogen|first2=J.|last2=Calambokidis|first3=E.|last3=Oleson|first4=J.|last4=Potvin|first5=N. D.|last5=Pyenson|first6= G.|last6=Schorr |first7=R. E.|last7=Shadwick |journal=Journal of Experimental Biology|year=2011|volume=214|issue=Pt 1|pages=131–146|doi=10.1242/jeb.048157|pmid=21147977|doi-access=free}}</ref> Gulp-feeders swim with an open mouth, filling it with water and prey. Prey must occur in sufficient numbers to trigger the whale's interest, be within a certain size range so that the baleen plates can filter it, and be slow enough so that it cannot escape.{{sfn|Perrin|2009|loc=pp. 806–813}}

[[File:sea otter with sea urchin.jpg|thumb|left|[[Sea otter]]s have dexterous hands which they use to smash sea urchins off rocks|alt=A sea otter floating on the water on its back holding a sea urchin with one hand and a rock in the other]]

Otters are the only marine animals that are capable of lifting and turning over rocks, which they often do with their front paws when searching for prey.<ref name=wp>{{cite video |people=Reitherman, Bruce (Producer and photographer) |date= 1993 |title=Waddlers and Paddlers: A Sea Otter Story–Warm Hearts & Cold Water |medium= Documentary |publisher= [[Public Broadcasting Service|PBS]]|location= U.S.A.}}</ref> The sea otter may pluck [[snail]]s and other organisms from kelp and dig deep into underwater mud for [[clam]]s.<ref name=wp/> It is the only marine mammal that catches fish with its forepaws rather than with its teeth.<ref name=nickerson21>Nickerson, p. 21</ref> Under each foreleg, sea otters have a loose pouch of skin that extends across the chest which they use to store collected food to bring to the surface. This pouch also holds a rock that is used to break open shellfish and clams, an example of [[tool use by sea otters|tool use]].<ref name=haley>{{cite book|title=Marine Mammals of Eastern North Pacific and Arctic Waters|edition=2nd|chapter=Sea Otter|year=1986|location=Seattle, Washington|publisher=Pacific Search Press|isbn=978-0-931397-14-1|editor= Haley, D.|oclc=13760343}}</ref> The sea otters eat while floating on their backs, using their forepaws to tear food apart and bring to their mouths.<ref name=bbc>{{cite web|title=Sea otter|url=https://www.bbc.co.uk/nature/life/Sea_otter|publisher=BBC|access-date=2007-12-31|archive-date=2010-12-03|archive-url=https://web.archive.org/web/20101203120833/http://www.bbc.co.uk/nature/life/Sea_otter|url-status=dead}}</ref><ref name=vanblaricom>{{cite book|title=Sea Otters|year=2001|last=VanBlaricom|first=Glenn R.|publisher=Voyageur Press Inc.|location=Stillwater, MN|pages=[https://archive.org/details/seaotters0000vanb/page/22 22, 33, 69]|isbn=978-0-89658-562-1|oclc=46393741|url=https://archive.org/details/seaotters0000vanb/page/22}}</ref> [[Marine otter]]s mainly feed on crustaceans and fish.<ref>{{cite journal|first1=J. C.|last1=Mangel|first2=T. |last2=Whitty|first3=G.|last3=Medina-Vogel|first4=J.|last4=Alfaro-Shigueto|first5=C.|last5=Cáceres|first6=B. J.|last6=Godley|year=2010|title=Latitudinal variation in diet and patterns of human interaction in the marine otter |journal=Marine Mammal Science|volume=27|issue=2|pages=14–25|doi=10.1111/j.1748-7692.2010.00414.x}}</ref>

Pinnipeds mostly feed on fish and [[cephalopod]]s, followed by crustaceans and [[bivalve]]s, and then [[zooplankton]] and warm-blooded prey (like [[sea bird]]s).<ref name=thepinnipeds/>{{rp|145}} Most species are [[Generalist and specialist species|generalist]] feeders, but a few are specialists.<ref>{{Cite book|author1=Lavinge, D. M. |author2=Kovacs, K. M. |author3=Bonner, W. N. |contribution=Seals and Sea lions|year=2001|title=The Encyclopedia of Mammals|edition= 2nd|editor=MacDonald, D.|publisher=Oxford University Press|pages=147–55|isbn=978-0-7607-1969-5|oclc=48048972}}</ref> They typically hunt non-schooling fish, slow-moving or immobile invertebrates or endothermic prey when in groups. Solitary foraging species usually exploit coastal waters, bays and rivers. When large schools of fish or squid are available, pinnipeds [[cooperative hunting|hunt cooperatively]] in large groups, locating and herding their prey. Some species, such as [[California sea lion|California]] and [[South American sea lion|South American]] sea lions, may forage with cetaceans and sea birds.<ref name=thepinnipeds/>{{rp|168}}

The polar bear is the most carnivorous species of bear, and its diet primarily consists of [[Ringed seal|ringed]] (''Pusa hispida'') and [[bearded seal|bearded]] (''Erignathus barbatus'') seals.<ref>{{cite episode |title=Arctic Bears |url=https://www.pbs.org/wnet/nature/arcticbears/index.html |series=PBS Nature |series-link=Nature (TV series) |airdate=17 February 2008 |url-status=dead |archive-url=https://web.archive.org/web/20080616221443/http://www.pbs.org/wnet/nature/arcticbears/index.html |archive-date=16 June 2008}}</ref> Polar bears hunt primarily at the interface between ice, water, and air; they only rarely catch seals on land or in open water.<ref>{{cite book |last1=Amstrup |first1=Steven C. |last2=Marcot |first2=Bruce G. |last3=Douglas |first3=David C. |year=2007 |title=Forecasting the range-wide status of polar bears at selected times in the 21st Century |location=Reston, Virginia |publisher=U.S. Geological Survey |url=http://www.plexusowls.com/PDFs/forecasting_polar_bears_amstrup_etal_lowres.pdf}}</ref> The polar bear's most common hunting method is still-hunting:<ref name="hemstock24-27">{{cite book|ref=Hemstock|title=The Polar Bear|last=Hemstock|first=Annie|year=1999|publisher=Capstone Press|location=Manakato, MN|isbn=978-0-7368-0031-0|oclc=38862448|pages=[https://archive.org/details/polarbear0000hems/page/24 24–27]|url=https://archive.org/details/polarbear0000hems/page/24}}</ref> The bear locates a seal breathing hole using its sense of smell, and crouches nearby for a seal to appear. When the seal exhales, the bear smells its breath, reaches into the hole with a forepaw, and drags it out onto the ice. The polar bear also hunts by stalking seals resting on the ice. Upon spotting a seal, it walks to within {{convert|100|yd|m|sigfig=1}}, and then crouches. If the seal does not notice, the bear creeps to within {{convert|30|to|40|ft|m|sigfig=1}} of the seal and then suddenly rushes to attack.<ref>{{cite book |ref=Matthews|title=Polar Bear |last=Matthews |first=Downs |year=1993 |publisher=Chronicle Books|location=San Francisco|isbn=978-0-8118-0204-8|oclc=488971350}}</ref> A third hunting method is to raid the birth lairs that female seals create in the snow.<ref name="hemstock24-27"/> They may also feed on fish.<ref name="ReferenceA">{{cite journal |author1=Dyck, M. G. |author2=Romberg, S. |title=Observations of a wild polar bear (''Ursus maritimus'') successfully fishing Arctic charr (''Salvelinus alpinus'') and Fourhorn sculpin (''Myoxocephalus quadricornis'') |journal=Polar Biology |date=2007 |volume=30 |issue=12 |pages=1625–1628 |doi=10.1007/s00300-007-0338-3|bibcode=2007PoBio..30.1625D |s2cid=31644963 }}</ref>

[[File:Dugong Marsa Alam.jpg|thumb|A [[dugong]] feeding on the sea-floor|alt=A dugong with its mouth on the sandy seafloor, leaving a noticeable cloud which hovers near the bottom. There are two yellow fish with black stripes near its mouth, and there are grasses poking out of the seafloor]]

Sirenians are referred to as "sea cows" because their diet consists mainly of seagrass. When eating, they ingest the whole plant, including the roots, although when this is impossible they feed on just the leaves.<ref>{{cite book |url={{Google books|plainurl=yes |id=p84IxiWkAX8C |page=112}} |first1=Helene |last1=Marsh |first2=Thomas J. |last2=O'Shea |first3=John E. |last3=Reynolds III|year=2012|title=Ecology and Conservation of the Sirenia: Dugongs and Manatees|publisher=Cambridge University Press|location=Cambridge |page=112|isbn=978-0-521-88828-8|oclc=773872519}}</ref> A wide variety of seagrass has been found in dugong stomach contents, and evidence exists they will eat [[algae]] when seagrass is scarce.<ref>{{cite book |last=Marsh |first=Helene |chapter= Dugongidae |title=Fauna of Australia|volume=1|publisher=Australian Government Public Service |location=Canberra|isbn=978-0-644-06056-1|oclc=27492815|year=1989 }}</ref> West Indian manatees eat up to 60 different species of plants, as well as fish and small invertebrates to a lesser extent.<ref>{{cite journal |first1=Aarin Conrad|last1=Allen |first2= Edward O.|last2=Keith |year=2015|title=Using the West Indian Manatee (''Trichechus manatus'') as a Mechanism for Invasive Aquatic Plant Management in Florida |journal=Journal of Aquatic Plant Management|volume=53|pages=95–104|url=https://nsuworks.nova.edu/cgi/viewcontent.cgi?article=1494&context=occ_facarticles/}}</ref>

===Keystone species===
{{Further|Keystone species}}
Sea otters are a classic example of a keystone species; their presence affects the ecosystem more profoundly than their size and numbers would suggest. They keep the population of certain [[benthic]] (sea floor) herbivores, particularly [[sea urchin]]s, in check. Sea urchins graze on the lower stems of [[kelp]], causing the kelp to drift away and die. Loss of the habitat and nutrients provided by kelp forests leads to profound [[Cascade effect (ecology)|cascade effects]] on the marine ecosystem. North Pacific areas that do not have sea otters often turn into [[urchin barren]]s, with abundant sea urchins and no kelp forest.<ref>{{Cite journal|title = Killer Whale Predation on Sea Otters Linking Oceanic and Nearshore Ecosystems|journal = Science|year=1998|issn = 0036-8075|pmid = 9774274|pages = 473–476|volume = 282|issue = 5388|doi = 10.1126/science.282.5388.473|first1 = J. A.|last1 = Estes|first2 = M. T.|last2 = Tinker|first3 = T. M.|last3 = Williams|first4 = D. F.|last4 = Doak|bibcode = 1998Sci...282..473E| s2cid=8925215 }}</ref> Reintroduction of sea otters to British Columbia has led to a dramatic improvement in the health of coastal ecosystems,<ref name=dfo>{{cite web|url=http://www.dfo-mpo.gc.ca/species-especes/profiles-profils/seaOtter-loutredemer-eng.html|title=Aquatic Species at Risk&nbsp;– Species Profile&nbsp;– Sea Otter|publisher=Fisheries and Oceans Canada|access-date=29 November 2007}}</ref> and similar changes have been observed as sea otter populations recovered in the Aleutian and Commander Islands and the [[Big Sur]] coast of California.<ref name = vanblaricom/> However, some kelp forest [[ecosystem]]s in California have also thrived without sea otters, with sea urchin populations apparently controlled by other factors.<ref name = vanblaricom/> The role of sea otters in maintaining kelp forests has been observed to be more important in areas of open coast than in more protected bays and [[estuaries]].<ref name=vanblaricom/>

{{Multiple image|align=left|image1=Antarctic Fur Seal Pups play amid Tussock Grass (5723988869).jpg|alt1=Two furry, dark-brown seal pups in the sand, sitting next to some tall, green grass|width2=150|image2=Blanchon-idlm2006.jpg|alt2=A white seal pup on the snowy ground with large black eyes and nose|footer=[[Antarctic fur seal]] pups (left) vs. Arctic [[harp seal]] pup (right)}}
An apex predator affects prey population dynamics and defense tactics (such as camouflage).<ref>Lepak, Jesse M.; Kraft, Clifford E., Weidel, Brian C. (March 2006). [http://www2.dnr.cornell.edu/cek7/Publications/Lepak_et_al_2006.pdf "Rapid food web recovery in response to removal of an introduced apex predator"] (PDF).  ''Canadian Journal of Fisheries and Aquatic Sciences'' '''63''' (3): 569–575. {{ISSN|0706-652X}}. {{open access}}</ref> The polar bear is the apex predator within its range.<ref name=apex1/> Several animal species, particularly [[Arctic fox]]es (''Vulpes lagopus'') and [[glaucous gull]]s (''Larus hyperboreus''), routinely scavenge polar bear kills.<ref name="behavior"/> The relationship between ringed seals and polar bears is so close that the abundance of ringed seals in some areas appears to regulate the density of polar bears, while polar bear predation in turn regulates density and reproductive success of ringed seals.<ref>{{cite book |last1=Amstrup |first1=Steven C. |last2=Marcot |first2=Bruce G. |last3=Douglas |first3=David C. |year=2007 |title=Forecasting the range-wide status of polar bears at selected times in the 21st Century |location=Reston, Virginia |publisher=U.S. Geological Survey |url=http://www.plexusowls.com/PDFs/forecasting_polar_bears_amstrup_etal_lowres.pdf}}</ref> The [[evolutionary pressure]] of polar bear predation on seals probably accounts for some significant differences between Arctic and [[Antarctica|Antarctic]] seals. Compared to the Antarctic, where there is no major surface predator, Arctic seals use more breathing holes per individual, appear more restless when hauled out on the ice, and rarely defecate on the ice.<ref name="behavior"/> The fur of Arctic pups is white, presumably to provide [[camouflage]] from predators, whereas Antarctic pups all have dark fur.<ref name="behavior">{{cite book |last1=Stirling |first1=Ian|first2=Dan |last2=Guravich|year=1988 |title=Polar Bears |location=Ann Arbor, MI|publisher=University of Michigan Press |pages=27–28|url={{Google books|plainurl=yes|id=ViOiGWPQRjIC|page=27}}|isbn=978-0-472-10100-9|oclc=757032303}}</ref>

Killer whales are apex predators throughout their global distribution, and can have a profound effect on the behavior and population of prey species. Their diet is very broad and they can feed on many vertebrates in the ocean including [[salmon]],<ref>{{cite book|first1=Lynne M.|last1=Barre|first2=J. B.|last2=Norberg|first3=Gary J.|last3=Wiles|year=2005|title=Conservation Plan for Southern Resident Killer Whales (''Orcinus orca'')|publisher=National Marine Fisheries Service (NMFS) Northwest Regional Office|location=Seattle|page=18|url=http://www.nwr.noaa.gov/Marine-Mammals/Whales-Dolphins-Porpoise/Killer-Whales/Conservation-Planning/upload/SRKW-propConsPlan.pdf|archive-url=https://web.archive.org/web/20080626121719/http://www.nwr.noaa.gov/Marine-Mammals/Whales-Dolphins-Porpoise/Killer-Whales/Conservation-Planning/upload/SRKW-propConsPlan.pdf|url-status=dead|archive-date=2008-06-26}}</ref> rays, sharks (even [[white shark]]s),<ref>{{cite journal|last1=Pyle|first1=Peter|last2=Schramm|first2=Mary Jane|last3=Keiper|first3=Carol|last4=Anderson|first4=Scot D.|year=1999|title=Predation on a white shark (''Carcharodon carcharias'') by a killer whale (''Orcinus orca'') and a possible case of competitive displacement|journal=Marine Mammal Science|volume=15|issue=2|pages=563–568|doi=10.1111/j.1748-7692.1999.tb00822.x|bibcode=1999MMamS..15..563P |url=http://www.prbo.org/cms/docs/marine/MMS.pdf|access-date=2016-08-02|archive-date=2012-03-22|archive-url=https://web.archive.org/web/20120322070431/http://www.prbo.org/cms/docs/marine/MMS.pdf|url-status=dead}}</ref><ref>{{cite journal|last=Visser|first=Ingrid N.|year=2005|title=First Observations of Feeding on Thresher (''Alopias vulpinus'') and Hammerhead (''Sphyrna zygaena'') Sharks by Killer Whales (''Orcinus orca'') Specialising on Elasmobranch Prey|journal=Aquatic Mammals|volume=31|issue=1|pages=83–88|doi=10.1578/AM.31.1.2005.83}}</ref> large baleen whales,<ref>{{cite journal|last1=Ford|first1=J. K. B.|last2=Reeves|first2=R. R.|year=2008|title=Fight or flight: antipredator strategies of baleen whales|journal=Mammal Review|volume=38|issue=1|pages=50–86|doi=10.1111/j.1365-2907.2008.00118.x|citeseerx=10.1.1.573.6671}}</ref> and nearly 20 species of pinniped.<ref>{{cite book|last1=Heimlich|first1=Sara|last2=Boran|first2=James|year=2001|title=Killer Whales|location=Stillwater, Minnesota|publisher=Voyageur Press|isbn=978-0-89658-545-4|oclc=46973039}}</ref> The predation of whale calves may be responsible for annual whale migrations to calving grounds in more tropical waters, where the population of killer whales is much lower than in polar waters. Prior to [[whaling]], it is thought that great whales were a major food source; however, after their sharp decline, killer whales have since expanded their diet, leading to the decline of smaller marine mammals.{{sfn|Perrin|2009|loc=[https://books.google.com/books?id=2rkHQpToi9sC&pg=PA360 p. 360]}} A decline in Aleutian Islands sea otter populations in the 1990s was controversially attributed by some scientists to killer whale predation, although with no direct evidence. The decline of sea otters followed a decline in [[harbor seal]] and [[Steller sea lion]] populations, the killer whale's preferred prey, which in turn may be substitutes for their original prey, now reduced by industrial whaling.<ref>{{cite journal|last1=Springer|first1=A. M.|title=Sequential megafaunal collapse in the North Pacific Ocean: An ongoing legacy of industrial whaling?|journal=Proceedings of the National Academy of Sciences|volume=100|pages=12223–12228|year=2003|doi=10.1073/pnas.1635156100|issue=21|bibcode=2003PNAS..10012223S|pmid=14526101|pmc=218740|doi-access=free}}</ref><ref>{{cite journal|last1=Demaster|first1=D|last2=Trites|first2=A|last3=Clapham|first3=P|last4=Mizroch|first4=S|last5=Wade|first5=P|last6=Small|first6=R|last7=Hoef|first7=J|title=The sequential megafaunal collapse hypothesis: Testing with existing data|journal=Progress in Oceanography|year=2006|doi=10.1016/j.pocean.2006.02.007|volume=68|issue=2–4|pages=329–342|bibcode=2006PrOce..68..329D}}</ref><ref>{{cite journal|last1=Estes|first1=J. A.|last2=Doak|first2=D. F.|last3=Springer|first3=A. M.|last4=Williams|first4=T. M.|title=Causes and consequences of marine mammal population declines in southwest Alaska: a food-web perspective|journal=Philosophical Transactions of the Royal Society B: Biological Sciences|volume=364|pages=1647–1658|year=2009|doi=10.1098/rstb.2008.0231|issue=1524|pmid=19451116|pmc=2685424}}</ref>

===Whale pump===
{{Main|Whale pump|Whale fall}}

[[File:Oceanic whale pump - journal.pone.0013255.g001.tiff|thumb|"Whale pump" – the role played by whales in recycling ocean nutrients<ref name=pump/>|alt=Fish and phytoplankton bring nutrients to the seafloor in the form of detritus, and whales bring nutrients up to the surface also in the form of detritus.]]

A 2010 study considered whales to be a positive influence to the productivity of ocean fisheries, in what has been termed a "whale pump". Whales carry nutrients such as [[Nitrogen cycle#Marine nitrogen cycle|nitrogen]] from the depths back to the surface. This functions as an upward [[biological pump]], reversing an earlier presumption that whales accelerate the loss of nutrients to the bottom. This nitrogen input in the [[Gulf of Maine]] is more than the input of all rivers combined emptying into the gulf, some {{convert|23000|MT|ST|order=flip}} each year.<ref name=pump>{{cite journal|last1=Roman|first1=J.|last2=McCarthy|first2=J. J.|year=2010|editor-last=Roopnarine|editor-first=Peter|title=The Whale Pump: Marine Mammals Enhance Primary Productivity in a Coastal Basin|journal=PLOS ONE|volume=5|issue=10|doi=10.1371/journal.pone.0013255|pmid=20949007|pages=e13255|bibcode=2010PLoSO...513255R|pmc=2952594|doi-access=free}}{{open access}}</ref>
[[Whale faeces|Whales defecate]] at the ocean's surface; their excrement is important for fisheries because it is rich in iron and nitrogen. The whale feces are liquid and instead of sinking, they stay at the surface where [[phytoplankton]] feed off it.<ref name=pump/><ref>{{cite journal|title=Whales as marine ecosystem engineers|author1=Roman, Joe|author2=Estes, James A.|author3=Morissette, Lyne|author4=Smith, Craig|author5=Costa, Daniel|author6=McCarthy, James|author7=Nation, J.B.|author8=Nicol, Stephen|author9=Pershing, Andrew|author10=Smetacek, Victor|journal=Frontiers in Ecology and the Environment|volume=12|issue=7|pages=377–385|doi=10.1890/130220|date=2014|bibcode=2014FrEE...12..377R |url=http://ecite.utas.edu.au/93252|access-date=2019-12-14|archive-url=https://web.archive.org/web/20200211170317/http://ecite.utas.edu.au/93252|archive-date=2020-02-11|url-status=dead}}</ref>

Upon death, whale carcasses fall to the deep ocean and provide a substantial habitat for marine life. Evidence of whale falls in present-day and fossil records shows that deep-sea whale falls support a rich assemblage of creatures, with a global diversity of 407 species, comparable to other [[neritic]] biodiversity hotspots, such as [[cold seep]]s and [[hydrothermal vent]]s.<ref>{{cite journal|last1=Smith|first1=Craig R.|last2=Baco|first2=Amy R.|year=2003|title=Ecology of Whale Falls at the Deep-Sea Floor|journal=Oceanography and Marine Biology: An Annual Review|volume=41|pages=311–354 |url=http://www.soest.hawaii.edu/oceanography/faculty/csmith/Files/Smith%20and%20Baco%202003.pdf}}</ref> Deterioration of whale carcasses happens through a series of three stages. Initially, moving organisms, such as [[shark]]s and [[hagfish]], scavenge soft tissue at a rapid rate over a period of months to as long as two years. This is followed by the colonization of bones and surrounding sediments (which contain organic matter) by enrichment opportunists, such as crustaceans and [[polychaetes]], throughout a period of years. Finally, sulfophilic bacteria reduce the bones releasing [[hydrogen sulphide]] enabling the growth of [[chemoautotrophic]] organisms, which in turn, support other organisms such as [[mussel]]s, clams, [[limpet]]s, and [[sea snail]]s. This stage may last for decades and supports a rich assemblage of species, averaging 185 species per site.<ref>{{cite journal |last1=Fujiwara|first1=Yoshihiro|first2=Masaru|last2=Kawato|first3=Tomoko|last3=Yamamoto|first4=Toshiro|last4=Yamanaka|first5=Waka|last5=Sato-Okoshi|first6=Chikayo|last6=Noda|first7=Shinji|last7=Tsuchida|first8=Tomoyuki |last8=Komai|first9=Sherine S.|last9=Cubelio|first10=Takenori|last10=Sasaki|first11=Karen|last11=Jacobsen|first12=Kaoru|last12=Kubokawa |first13=Katsunori|last13=Fujikura|first14=Tadashi|last14=Maruyama|first15=Yasuo |last15=Furushima|first16=Kenji|last16=Okoshi|first17=Hiroshi|last17=Miyake|first18=Masayuki|last18=Miyazaki|first19=Yuichi|last19=Nogi|first20=Akiko|last20=Yatabe|first21=Takashi|last21=Okutani|title=Three-year investigations into sperm whale-fall ecosystems in Japan |journal=Marine Ecology |volume=28 |issue=1 |pages=219–230|year=2007|doi=10.1111/j.1439-0485.2007.00150.x|bibcode=2007MarEc..28..219F|doi-access=free}}{{open access}}</ref>